The blast in a shopping area close to the northwestern city's main Khyber Bazaar also wounded more than 100 people, provincial health minister Zahir Ali Shah told reporters.

"At least 49 people were killed and more than 100 injured in the blast," Shah told reporters in the main Lady Reading Hospital.

Doctor Mehboob Ali at the hospital confirmed the toll and put the number of wounded at 103. The injured included women and children, he said.

More than 50 people were in serious condition, he said.

Police official Mohammad Karim estimated the size of the bomb at around 100 kilogrammes (220 pounds), while Shafqat Malik, chief of the bomb disposal squad, confirmed that a suicide attacker had detonated the bomb.

The device was planted in the door panels of the vehicle and included machinegun ammunition, designed to cause maximum casualties, Malik said.

"The suicide attacker was sitting in the vehicle," he added.

Another police official, Nisar Marwat, said the death toll could rise, given that some of the wounded were in critical condition.

"We have declared an emergency in the hospitals," Local administration chief Sahibzada Mohammad Anis told reporters.